How to put your company seal and signature on a PDF
Photograph your seal on white paper and place it with Add image, then tap Then and add your signature with Sign. For a ready-made PAID, RECEIVED or APPROVED stamp, Mark up has those built in.
Add imageFree. Nothing is uploaded.
How to do it
- Stamp your seal on plain white paper, photograph it in daylight, and remove the background in a photo app that saves PNG.
- Open Add image, add the PDF, and tap Choose a photo, a logo or a stamp to pick the seal picture.
- Tap the page where the seal goes, drag it into place, size it by its corner, and press Place it.
- Tap Then, choose Sign, draw your signature and tap where it goes.
- Press Place the signature and save the sealed, signed PDF.
A clean picture of the seal
Press the seal once, firmly, with fresh ink, on clean white paper. Photograph it from straight above in daylight, close enough that the seal fills most of the photo, with no shadow across it. A crisp, even impression matters more than the camera.
A JPEG photo always carries its white paper with it, which shows as a white patch on a letterhead with a coloured band or over printed lines. Remove the background in your phone’s photo editor, or any app that saves a PNG with a see-through background, and the seal sits on the page like real ink. Do this well once, keep the finished PNG somewhere safe, and reuse it.
Placing the seal and the signature
Add image puts the picture where you tap and keeps its shape as you resize it, so a round seal stays round. Tap another page to place it there too; each copy moves and sizes on its own. Large photos are shrunk to a sensible size first, so a phone photo does not add megabytes to the PDF.
Then the signature: Sign lets you draw it with a finger or a mouse, in blue or black, and place it the same way. Many businesses sign across the edge of the seal, as on paper; others sign above the printed name with the seal beside it. If the document has no printed place for your name, designation and the date, write them with Add text.
Ready-made office stamps
For marks that are words rather than a seal, Mark up has stamps built in: Approved, Paid, Received, Draft, Confidential, Urgent, Copy and Void, or your own words, such as RECEIVED 12 OCT 2026, set in capitals in black, blue or red. Choose Stamp, pick one, tap the page and drag its corner to size it. They suit an accounts desk marking bills paid or received, or a draft that must not be mistaken for the final copy.
A picture, or a digital signature?
A seal and signature placed this way are pictures on the page, as on a scan of a stamped paper. That is what most quotations, purchase orders, letters and invoices sent by email carry. It does not prove who placed them, and anyone with the file could copy the picture, so send stamped copies only to the people who need them.
Where a document must show who signed and that nothing changed since, as some filings and tenders require, a certificate-based digital signature is the tool, added last, after the seal and every other change; see digitally sign a PDF with your DSC. Whether a stamped PDF is enough depends on who receives it, so ask when it matters.
A worked example
Suresh runs a small printing shop and sends quotations as PDFs from his laptop. He stamps his round seal on white paper once, photographs it, removes the background in a photo app and saves it as seal.png. For each quotation, he opens Add image, adds the PDF, chooses seal.png, taps near the bottom right of the last page and sizes the seal to about the width of his printed name. He presses Place it, taps Then, chooses Sign, draws his signature across the seal’s lower edge and presses Place the signature. The file he emails looks like a stamped paper quotation, and neither it nor his seal was ever uploaded anywhere.
Common mistakes
A seal photographed at an angle comes out oval and smudged: hold the phone straight above it. A seal placed too large looks odd; on an A4 page most seals are only a few centimetres across, so compare it with the text around it. And sealing every page of a long document one by one, when the page that needs it is usually only the last, or the one with the signature block.
Questions people ask
Are my seal and signature stored on your site?
No. They are placed on the page in your browser and forgotten when you leave. Nothing is uploaded, and nothing is kept.
Can I place the seal and signature in one go?
Yes. Sign across the seal on white paper, photograph the two together, and place that one picture with Add image.
Why is there a white box around my seal?
The picture is a JPEG, or a PNG with a white background. Remove the background in a photo app and save it as PNG.
Can I do this on my phone?
Yes. Every step works in a phone’s browser. Pinch to zoom in before placing, so the seal lands exactly where you want it.
Is a stamped and signed PDF legally valid?
It depends on the document and who receives it. Many businesses accept one for quotations, invoices and letters; filings that require a digital signature need a certificate.
Your file stays on your device. Foolscap does the work inside your browser, so nothing is uploaded and there is nothing for anyone to keep. How you can check